Assessing the potential impact of extending antenatal steroids to the late preterm period

Gestational diabetes mellitus and late preterm birth: outcomes with and without antenatal corticosteroid exposure

BACKGROUND

Unlike pregestational diabetes mellitus, the American College of Obstetricians and Gynecologists recommends antenatal corticosteroids in those with gestational diabetes mellitus at risk for preterm birth. However, this recommendation is based on limited data, only 10.6% of the Antenatal Late Preterm Steroids study sample had gestational diabetes mellitus. There is a paucity of data on the risk of neonatal respiratory and other morbidity in this population.

OBJECTIVE

This study aimed to examine respiratory outcomes in parturients with gestational diabetes mellitus who received antenatal corticosteroids and delivered during the late preterm period vs those who did not.

STUDY DESIGN

This population-based cohort study used the US Vital Statistics dataset between 2016 to 2020. The inclusion criteria were singleton, nonanomalous individuals who delivered between 34.0 to 36.6 weeks with gestational diabetes mellitus and known status of antepartum corticosteroid exposure. The primary outcome, a composite neonatal adverse outcome, included Apgar score <5 at 5 minutes, immediate assisted ventilation, assisted ventilation >6 hours, surfactant use, seizure, or neonatal mortality. The secondary outcome was a composite maternal adverse outcome, including maternal blood transfusion, ruptured uterus, unplanned hysterectomy, and admission to the intensive care unit. Multivariable Poisson regression models were used to estimate adjusted relative risks and 95% confidence intervals. Average annual percent change was calculated to assess changes in rates of corticosteroid exposure over the study period.

RESULTS

Of 19 million births during the study period, 110,197 (0.6%) met the inclusion criteria, and among them, 23,028 (20.9%) individuals with gestational diabetes mellitus received antenatal corticosteroids. The rate of antenatal steroid exposure remained stable over the 5 years (APC=10.7; 95% confidence interval, -5.4 to 29.4). The composite neonatal adverse outcome was significantly higher among those who received corticosteroids than among those who did not (137.1 vs 216.5 per 1000 live births; adjusted relative risk 1.24; 95% confidence interval, 1.20-1.28). Three components of the composite neonatal adverse outcome-immediate assisted ventilation, intubation >6 hours, and surfactant use-were significantly higher with exposure than without. In addition, the composite maternal adverse outcome was significantly higher among those who received corticosteroids (adjusted relative risk, 1.34; 95% confidence interval, 1.18-1.52). Three components of the composite maternal adverse outcome-admission to intensive care unit, blood transfusion, and unplanned hysterectomy-were significantly higher among the exposed group. Subgroup analysis, among large for gestational age, by gestational age, and race and ethnicity, confirm the trend of increased likelihood of adverse outcomes with exposure to corticosteroid.

CONCLUSION

Individuals with gestational diabetes mellitus and antenatal corticosteroid exposure, who delivered in the late preterm, were at higher risk of neonatal and maternal adverse outcomes than those unexposed to corticosteroid.

Antenatal Corticosteroid Prophylaxis at Late Preterm Gestation: Clinical Guidelines vs Clinical Practice

OBJECTIVES

We investigated how the Antenatal Late Preterm Steroids (ALPS) trial findings have been translated into clinical practice in Canada and the United States (U.S.).

METHODS

The study included all live births in Nova Scotia, Canada and the United States from 2007 to 2020. ACS administration within specific categories of gestational age was assessed by calculating rates per 100 live births, and temporal changes were quantified using odds ratios (OR) and 95% CI. Temporal trends in optimal and suboptimal ACS use were also assessed.

RESULTS

In Nova Scotia, the rate of any ACS administration increased significantly among women delivering at 35⁰ to 36⁶ weeks, from 15.2% in 2007-2016 to 19.6% in 2017-2020 (OR 1.36, 95% CI 1.14-1.62). Overall, the U.S. rates were lower than the rates in Nova Scotia. In the U.S., rates of any ACS administration increased significantly across all gestational age categories: among live births at 35⁰ to 36⁶ weeks gestation, any ACS use increased from 4.1% in 2007-2016 to 18.5% in 2017-2020 (OR 5.33, 95% CI 5.28-5.38). Among infants between 24⁰ and 34⁶ weeks gestation in Nova Scotia, 32% received optimally timed ACS, while 47% received ACS with suboptimal timing. Of the women who received ACS in 2020, 34% in Canada and 20% in the U.S. delivered at ≥37 weeks.

CONCLUSION

Publication of the ALPS trial resulted in increased ACS administration at late preterm gestation in Nova Scotia, Canada and the U.S. However, a significant fraction of women receiving ACS prophylaxis delivered at term gestation.

A case-control study on the effects of incomplete, one, and more than one dexamethasone course on acute respiratory problems in preterm neonates born between 280 and 366 weeks of gestation

OBJECTIVE

To compare the effects of an incomplete course and more than 1 course of dexamethasone, relative to a control of a single complete course, on foetal respiratory problems and other adverse outcomes of preterm birth.

METHODS

This was a retrospective chart review of 1800 women with preterm delivery. Data were collected on newborns whose mothers administered 1 full course of dexamethasone (916/1800; 50.9%), a partial course (716/1800; 39.8%) and more than 1 course (168/1800; 9.3%). Demographic data and adverse maternal and neonatal outcomes were recorded.

RESULTS

Preterm singleton newborns whose mothers received several steroid hormone courses were significantly more likely to have adverse outcomes than newborns of mothers given 1 course. The negative outcomes were the need for positive pressure ventilation ([aOR] 1.831; 95% CI, (1.185,2.829); P = 0.019), ventilator support ([aOR] 1.843; 95% CI, (1.187,2.861); P = 0.011), and phototherapy ([aOR] 1.997; 95% CI, (1.378,2.895); P <  0.001), transient tachypnoea of the newborn ([aOR] 1.801; 95% CI, (1.261,2.571); P = 0.002), intraventricular haemorrhage ([aOR] 2.215; 95% CI, (1.159, 4.233); P = 0.027), sepsis ([aOR] 1.737; 95% CI, (1.086, 2.777); P = 0.007), and admission to neonatal intensive care ([aOR] 1.822; 95% CI, (1.275,2.604); P = 0.001). In the group of very preterm infants, newborns of mothers administered an incomplete course had developed respiratory distress syndrome (RDS) ([aOR] 3.177; 95% CI, (1.485, 6.795); P = 0.006) and used ventilatory support ([aOR] 3.565; 95% CI, (1.912, 6.650); P <  0.001) more than those of mothers receiving a single course.

CONCLUSIONS

Preterm singleton newborns whose mothers were given multiple courses of dexamethasone had an increased incidence of RDS and other adverse outcomes than those of mothers receiving a full course. However, very preterm newborns whose mothers were administered 1 full dexamethasone course had a significantly lower incidence of RDS than those whose mothers were given partial courses.

Impact on neonatal morbidities after a change in policy to administer antenatal corticosteroids to mothers at risk for late preterm delivery

OBJECTIVES

Antenatal corticosteroids (ACS) administered to mothers at risk for preterm delivery before 34 weeks has been standard care to improve neonatal outcomes. After introducing a new obstetric policy based on updated recommendations advising the administration of ACS to pregnant women at risk for late preterm (LPT) delivery (34-36 6/7 weeks), we set out to determine the short-term clinical impact on those LPT neonates.

METHODS

Retrospective chart review of LPT neonates delivered at NYU Langone Medical Center both one year before and after the policy went into place. We excluded subjects born to mothers with pre-gestational diabetes, multiple gestations, and those with congenital/genetic abnormalities. We also excluded subjects whose mothers already received ACS previously in pregnancy. Subjects were divided into pre-policy and post-policy groups. Neonatal and maternal data were compared for both groups.

RESULTS

388 subjects; 180 in the pre-policy and 208 in the post-policy group. This policy change resulted in a significant increase in ACS administration to mothers who delivered LPT neonates (67.3 vs. 20.6%, p<0.001). In turn, there was a significant reduction in LPT neonatal intensive care unit (NICU) admissions (44.2 vs. 54.4%, p=0.04) and need for respiratory support (27.9 vs. 42.8%, p<0.01). However, we also found an increased incidence of hypoglycemia (49.5 vs. 28.3%, p<0.001).

CONCLUSIONS

This LPT ACS policy appears effective in reducing the need for LPT NICU level care overall. However, clinicians must be attentive to monitor for adverse effects like hypoglycemia, and there remains a need for better understanding of potential long-term impacts.

Elucidating the Effect of Antenatal Corticosteroids in the Late Preterm Period

Aim and Objective

To determine the efficacy of antenatal corticosteroids given in the late preterm period.

Methodology

We conducted a retrospective case–control study on patients with singleton pregnancies who were at a risk of delivering in the late preterm period (34 weeks to 36 weeks 6 days). A total of 126 patients who had received antenatal corticosteroids (prenatal administration of either betamethasone or dexamethasone, minimum one dose) during the late preterm period were taken as cases, and 135 patients who had not received steroids antenatally due to various reasons, for example, who were clinically unstable, presented with active bleeding, non-reassuring foetal status that obligated an imminent delivery and those in active labour were included as controls. The various neonatal outcomes like APGAR score at one and five minutes, incidence of admission and duration of stay in neonatal intensive care unit (NICU), respiratory morbidity, requirement of assisted ventilation, intraventricular haemorrhage (IVH) necrotizing enterocolitis, transient tachypnea of the newborn, respiratory distress syndrome, use of surfactant, neonatal hypoglycaemia, hyperbilirubinemia requiring phototherapy, sepsis and neonatal mortality were compared between the two groups.

Results

The baseline characteristics of both groups were comparable. There was a lower incidence of admissions to neonatal intensive care unit (NICU) (15% vs. 26%, p = 0.05), respiratory distress syndrome (5% vs. 13%, p = 0.04), requirement of invasive ventilation (0% vs. 4%, p = 0.04) and hyperbilirubinemia requiring phototherapy (24% vs. 39%, p = 0.02) in the babies of the group that received steroids compared to the control group. The rate of overall respiratory morbidity in the neonates was lowered after giving steroids (16% vs. 28%, p = 0.04). The incidence of neonatal necrotizing enterocolitis, hypoglycaemia, IVH, TTN, sepsis and mortality between the two groups was not significant (p > 0.05).

Conclusion

Antenatal corticosteroids administered to patients between 34 and 36 weeks 6 days of gestation reduce respiratory morbidity, requirement of invasive ventilation, respiratory distress syndrome, hyperbilirubinemia requiring phototherapy and the incidence of NICU admissions in the newborns.

Indication Creep of Antenatal Late Preterm Steroids

OBJECTIVE

While antenatal corticosteroids (ACS) administered in the late preterm period have been shown to reduce respiratory morbidity, this finding was demonstrated in a well-designed randomized controlled trial (the Antenatal Betamethasone for Women at Risk for Late Preterm Delivery [ALPS]) with strict inclusion/exclusion criteria that may differ from clinical practice. The aim of this study was to investigate whether there has been indication creep since use of late preterm ACS became standard of care.

STUDY DESIGN

Retrospective cohort study of pregnant women who received late preterm ACS between 2016 and 2019 were identified and separated into epochs of 2016 to 2017 and 2018 to 2019 based on year of exposure. The primary outcome was rate of inappropriate ACS exposure, defined as nonadherence to the inclusion/exclusion criteria of the ALPS trial. Secondary outcomes were rates of nonoptimal ACS exposure (delivery >7 days from ACS or term delivery). Logistic regression was used to generate adjusted odds ratios (aORs) between epochs for the primary outcome adjusting for confounders.

RESULTS

There were 660 women who received late preterm ACS during the study period with 229 (34.6 %) deemed inappropriate exposures. The most common reason for inappropriate treatment was preterm premature rupture of membrane (PPROM; 29.0%) with exclusionary cervical examination or contraction frequency. No difference was observed in inappropriate ACS exposure between epochs (aOR = 0.83, 95% confidence interval [CI]: 0.59-1.2). However, there was a reduction in nonoptimal exposure over time (aOR = 0.67, 95% CI: 0.47-0.97) . Women receiving inappropriate ACS were more likely to deliver at term if indicated for maternal/fetal status (50.0 vs. 19.5%, p < 0.001) and preterm labor (66.0 vs. 41.9%; p = 0.015). Further, inappropriate exposure in preterm labor had higher rates of exposure latency >7 days (62.3 vs. 39.1%, p = 0.006) with a longer latency to delivery (3 vs. 16 days; p < 0.001).

CONCLUSION

Over one-third of women received late preterm ACS for an indication that could be classified as indication creep. Depending on indication, inappropriate administration is associated with higher rates of nonoptimal exposure.

KEY POINTS

· There is potential for indication creep of ACS administration.. · One third of late preterm ACS exposures in our study were inappropriate.. · Utilizing clinical criteria can aid in identifying patients who best benefit from late preterm ACS..

The impact of the Antenatal Late Preterm Steroids trial on the administration of antenatal corticosteroids

BACKGROUND

In 2016 the Antenatal Late Preterm Steroids study was published, demonstrating that antenatal corticosteroid therapy given to women at risk of late preterm delivery reduces respiratory morbidity in infants. However, the administration of antenatal corticosteroid therapy in late-preterm infants remains controversial. Late-preterm infants do not suffer from the same rates of morbidity as early-preterm infants, and the short-term benefits of antenatal corticosteroid therapy are less pronounced; consequently, the risk of possible harm is more difficult to balance.

OBJECTIVE

This study aimed to evaluate the association between the publication of the Antenatal Late Preterm Steroids study or the subsequent changes in guidelines and the rates of antenatal corticosteroid therapy administration in late-preterm infants in the United States.

STUDY DESIGN

Data analyzed were publicly available US birth certificate data from January 1, 2016 to December 31, 2018. An interrupted time series design was used to analyze the association between publication of the Antenatal Late Preterm Steroids study and changes in monthly rates of antenatal corticosteroid administration in late preterm gestation (34+0 to 36+6 weeks). Births at 28+0 to 31+6 weeks' gestation were used as a control. Antenatal corticosteroid therapy administration in women with births at 32+0 to 34+6 weeks was explored to analyze whether the intervention influenced antenatal corticosteroid therapy administration in women in the subgroup approaching 34 weeks' gestation. Antenatal corticosteroid therapy administration in women with term births (>37 weeks' gestation) was analyzed to explore if the intervention influenced the number of term babies exposed to antenatal corticosteroid therapy. Our regression model allowed analysis of both step and slope changes. February 2016 was chosen as the intervention period.

RESULTS

Our sample size was 18,031,950 total births. Of these, 1,056,047 were births at 34+0 to 36+6 weeks' gestation, 123,788 at 28+0 to 31+6 weeks, 153,708 at 32 to 33 weeks, and 16,602,699 were term births. There were 95,708 births at <28 weeks' gestation. There was a statistically significant increase in antenatal corticosteroid therapy administration rates in late preterm births following the online publication of the Antenatal Late Preterm Steroids study (adjusted incidence rate ratio, 1.48; 95% confidence interval, 1.36-1.61; P=.00). A significant increase in antenatal corticosteroid therapy administration rates was also seen in full-term births following the online publication of the Antenatal Late Preterm Steroids study. No significant changes were seen in antenatal corticosteroid administration rates in gestational age groups of 32+0 to 33+6 weeks or 28+0 to 31+6 weeks.

CONCLUSION

Online publication of the Antenatal Late Preterm Steroids study was associated with an immediate and sustained increase in the rates of antenatal corticosteroid therapy administration in late preterm births across the United States, demonstrating a swift and successful implementation of the Antenatal Late Preterm Steroids study guidance into clinical practice. However, there is an unnecessary increase in full-term infants receiving antenatal corticosteroid therapy. Given that the long-term consequences of antenatal corticosteroid therapy are yet to be elucidated, efforts should be made to minimize the number of infants unnecessarily exposed to antenatal corticosteroid therapy.

Prediction of Lung Maturity in Fetuses with Growth Restriction through Quantitative Ultrasound Analysis

The present study aimed to evaluate the performance of QuantusFLM software, which performs quantitative analysis of lung tissue texture through ultrasound images, in predicting lung maturity in fetal growth restriction (FGR). We included patients with singleton gestations between 34 and 38 6/7 wk and divided them into two groups: FGR and control (appropriate for gestational age [AGA]). The images were captured by ultrasound according to a specific protocol up to 48 h before delivery and analyzed with QuantusFLM software. The main clinical outcome evaluated was lung maturity (i.e., the absence of neonatal respiratory morbidity). We included 111 patients; one was excluded because of low image quality, leaving 55 patients in each group. The FGR group had a lower birth weight (2207 g vs. 2891 g, p < 0.001) and a longer stay in the neonatal intensive care unit (NICU) (10 d vs. 5 d, p = 0.043). QuantusFLM software was able to predict lung maturity in FGR with accuracy, sensitivity, specificity and positive and negative predictive values of 94.5%, 96.2%, 50%, 98.1% and 33.3%, respectively. QuantusFLM had good accuracy in predicting lung maturity in FGR with reliability in identifying pulmonary maturity.

Neonatal hypoglycemia after antenatal late preterm steroids in individuals with diabetes

OBJECTIVE

To establish whether administration of antenatal late preterm steroids to pregnant people with diabetes resulted in higher risk of neonatal hypoglycemia.

STUDY DESIGN

This is a retrospective cohort study of individuals with pre-gestational or gestational diabetes admitted between 34 0/7-36 6/7 weeks' gestation before and after introduction of an antenatal late preterm steroids protocol. The primary outcome was any neonatal blood glucose ≤ 60 mg/dL in the first 24 h of life.

RESULTS

Of 123 mother-neonate pairs, 52.8% (N = 65) delivered during the post-protocol period; 75.4% of those (N = 49) received late preterm steroids. 59.7% (N = 34) of the pre-protocol neonates and 81.5% (N = 53) of the post-protocol neonates had hypoglycemia (p = 0.008). After controlling for gestational age at delivery and mode of delivery, neonates in the post-protocol group had increased odds of hypoglycemia (adjusted odds ratio 2.96, 95% confidence interval 1.29-6.82).

CONCLUSION

Neonates born to mothers with diabetes who received late preterm corticosteroids experienced greater odds of hypoglycemia.

Respiratory and glycemic control outcomes of late preterm infants after antenatal corticosteroid exposure

OBJECTIVE

To quantify changes in respiratory and glycemic control outcomes following antenatal corticosteroids (ANCS) exposure in late preterm neonates.

DESIGN/METHODS

The study included 500 neonates born between 34 0/7 and 36 6/7 weeks of gestation. Study population was divided into two groups: an immature group (34 0/7-35 6/7 weeks) and a mature group (36 0/7-36 6/7 weeks). Respiratory and glycemic control outcomes were analyzed for each group independently.

RESULTS

In the immature group, the odds of developing respiratory distress decreased in neonates exposed to ANCS within 7 days of delivery (aOR 0.42; p = 0.02). In the mature group, ANCS exposure did not change respiratory outcomes, but decreased lowest blood glucose levels (-1.5 ± 0.66 mg/dL per dose, p = 0.02).

CONCLUSION

In our study cohort, ANCS administration was associated with improved neonatal respiratory outcomes only for infants in the immature 34 0/7-35 6/7 weeks of gestational age group. ANCS was associated with altered glycemic control only in infants in the mature 36 0/7-36 6/7 weeks of gestational age group.

Race and neonatal respiratory morbidity in the late preterm period

BACKGROUND

Prematurity is one of the leading causes of perinatal morbidity and mortality. Some studies suggest that respiratory disease may differ by race in early preterm infants. However, the role of race in late preterm neonatal morbidity is not yet established.

OBJECTIVE

The objective of our study was to determine whether neonatal respiratory morbidity differs by race in neonates born late preterm.

STUDY DESIGN

This was a secondary analysis of a randomized trial of women at high risk for late preterm delivery (Antenatal Late Preterm Steroids). Our study was limited to women with nonanomalous, singleton gestations, delivering between 34+0 to 36+6 weeks. Women were categorized into 4 groups by race: Black, White, Asian, or other/mixed. The primary outcome was a neonatal composite of treatment in the first 72 hours (continuous positive airway pressure or high-flow nasal cannula >2 hours, oxygen >4 hours, extracorporeal membrane oxygenation or mechanical ventilation) or stillbirth or neonatal death before 72 hours. The secondary outcomes included severe respiratory morbidity (the primary outcome extending continuous positive airway pressure or high-flow nasal cannula to >12 continuous hours and oxygen to at least 24 continuous hours), respiratory distress syndrome, transient tachypnea of the newborn, apnea, neonatal intensive care unit admission, bronchopulmonary dysplasia, and surfactant administration. The primary and secondary outcomes were assessed in the active (steroid) and placebo groups separately. We fit a logistic regression model to adjust for confounders related to respiratory morbidity.

RESULTS

Of a total of 2331 included women, 26.9% (n=627) were Black/African American, 57.1% (n=1333) White, 3.56% (n=83) Asian, and 12.36% (n=288) were other/mixed. In the placebo group, the rate of the primary outcome was significantly higher in Whites (18.6%) and Asians (22.8%) compared with the African American/Black group (12.3%) (P=.03). Adjusting for confounders, the primary outcome was not significant between the groups. The primary predictor for respiratory morbidity was a prior pregnancy with neonatal respiratory morbidity. Findings were similar in the steroid group, but severe respiratory morbidity was less common in Black infants compared with White infants (adjusted odds ratio, 0.45; 95% confidence interval, 0.24-0.83). However, a prior pregnancy with neonatal respiratory complications was no longer associated with respiratory morbidity after receipt of betamethasone.

CONCLUSION

Late preterm respiratory morbidity was similar between racial groups. Although a history of pregnancy with previous neonatal respiratory disease is the strongest risk factor for recurrence, this risk factor is mitigated by the receipt of steroids.

Inhibition of the NLRP3 inflammasome can prevent sterile intra-amniotic inflammation, preterm labor/birth, and adverse neonatal outcomes†

Sterile intra-amniotic inflammation is commonly observed in patients with spontaneous preterm labor, a syndrome that commonly precedes preterm birth, the leading cause of perinatal morbidity and mortality worldwide. However, the mechanisms leading to sterile intra-amniotic inflammation are poorly understood and no treatment exists for this clinical condition. Herein, we investigated whether the alarmin S100B could induce sterile intra-amniotic inflammation by activating the NLRP3 inflammasome, and whether the inhibition of this pathway could prevent preterm labor/birth and adverse neonatal outcomes. We found that the ultrasound-guided intra-amniotic administration of S100B induced a 50% rate of preterm labor/birth and a high rate of neonatal mortality (59.7%) without altering the fetal and placental weights. Using a multiplex cytokine array and immunoblotting, we reported that S100B caused a proinflammatory response in the amniotic cavity and induced the activation of the NLRP3 inflammasome in the fetal membranes, indicated by the upregulation of the NLRP3 protein and increased release of active caspase-1 and mature IL-1β. Inhibition of the NLRP3 inflammasome via the specific inhibitor MCC950 prevented preterm labor/birth by 35.7% and reduced neonatal mortality by 26.7%. Yet, inhibition of the NLRP3 inflammasome at term did not drastically obstruct the physiological process of parturition. In conclusion, the data presented herein indicate that the alarmin S100B can induce sterile intra-amniotic inflammation, preterm labor/birth, and adverse neonatal outcomes by activating the NLRP3 inflammasome, which can be prevented by inhibiting such a pathway. These findings provide evidence that sterile intra-amniotic inflammation could be treated by targeting the NLRP3 inflammasome.

Antenatal corticosteroid administration for foetal lung maturation

Antenatal corticosteroids are an essential component in the management of women at risk for preterm labour. They promote lung maturation and reduce the risk of other preterm neonatal complications. This narrative review discusses the contentious issues and controversies around the optimal use of antenatal corticosteroids and their consequences for both the mother and the neonate. The most recent evidence base is presented.

Institutional prevalence of class III obesity modifies risk of adverse obstetrical outcomes

BACKGROUND

Women with prepregnancy class III obesity (body mass index ≥40 kg/m²) are at an increased risk of perinatal complications and adverse obstetrical outcomes. Estimates of the magnitude of risk that these women face vary widely, which may reflect differences in institutional experience caring for women with obesity.

OBJECTIVE

We sought to characterize the relationship between institutional prevalence of prepregnancy class III obesity and the risk of adverse perinatal outcomes among these women, hypothesizing that higher-prevalence institutions would have lower rates of adverse maternal and perinatal outcomes among this population.

STUDY DESIGN

We conducted a retrospective cohort study using chart-abstracted data on births in Washington state from Jan. 1, 2012, to Dec. 31, 2017. The analysis was restricted to hospitals that delivered at least 1 patient per month with prepregnancy class III obesity. Institutional prevalence of prepregnancy class III obesity was calculated, and hospitals were classified as either high or low prevalence. We included nulliparous women with vertex-presenting singleton pregnancies at ≥37 weeks of gestation. We excluded births with missing initial body mass index. The primary outcome was the incidence of cesarean delivery. Secondary outcomes were induction of labor, postpartum complications, postpartum readmission, and neonatal intensive care unit admissions. We compared outcomes between women with prepregnancy class III and all obesity at high- and low-prevalence hospitals using the χ² test or the Fishers exact test as appropriate. Binary logistic regression was performed to compare outcomes at high- and low-prevalence hospitals. A hospital-adjusted multivariable regression model that controlled for baseline institutional rates of each outcome and compared outcomes between high- and low-prevalence hospitals was developed. A final multivariable logistic regression that controlled for both baseline institutional variation as well as potential clinical confounders was performed.

RESULTS

A total of 20,556 women at 6 hospitals were eligible for inclusion; the prevalence of prepregnancy class III obesity was 6.2% and 2.1% in high- and low-prevalence hospitals, respectively. Obese women, including those with class III obesity in a high-prevalence hospital, were more likely to be Latina and less likely to be of advanced maternal age and carry private insurance. After adjusting for the institutional cesarean delivery rate, women with prepregnancy class III obesity had significantly increased odds of cesarean delivery (odds ratio, 1.53, 95% confidence interval, 1.12-2.10); however, after adjusting for significant covariates, the association no longer achieved significance (odds ratio, 1.68, 95% confidence interval, 0.97-2.94). The hospital-adjusted odds of postpartum readmission were significantly increased for women with prepregnancy class III obesity when delivering in low-prevalence institutions (odds ratio, 6.61, 95% confidence interval, 1.93-22.56), and the association was further strengthened after controlling for significant covariates (odds ratio, 15.20, 95% confidence interval, 2.32-99.53). None of the models demonstrated significantly different odds of induction of labor, postpartum complications, or neonatal intensive care unit admission by institutional prevalence of prepregnancy class III obesity.

CONCLUSION

Even after controlling for underlying hospital and subject characteristics, women with prepregnancy class III obesity had significantly increased odds of postpartum readmission, and a trend toward increased odds of cesarean delivery, when delivering in institutions with less experience caring for women with obesity.

The place of antenatal corticosteroids in late preterm and early term births

Infants born in the late preterm period and via non-labour caesarean section in the early term period are at increased risk of respiratory morbidity when compared to their term-born counterparts. The morbidity in these infants is less frequent and severe than in early preterm infants. Antenatal corticosteroids reduce respiratory morbidity in these populations; however, the magnitude of the reduction appears to be small and predominantly in the self-limiting condition of transient tachypnoea of the neonate. The smaller benefit, along with possible harmful effects of corticosteroids, raises a question about the role of antenatal corticosteroids in this population. Special obstetric populations such as twin pregnancies and pregnancies complicated by diabetes and growth restriction are at increased risk of prematurity and more vulnerable to its complications. Nevertheless, there is limited evidence regarding the benefits of corticosteroids in these populations and potential concern regarding adverse effects. We recommend an individualised approach when administering corticosteroids at later gestations. In these specific obstetric populations, we do not currently recommend administering corticosteroids in the late preterm/early term periods until more evidence is available.

Antenatal corticosteroids: an assessment of anticipated benefits and potential risks

Antenatal corticosteroids are standard of care for pregnancies at risk of preterm delivery between 24-34 weeks' gestational age. Recent trials demonstrate modest benefits from antenatal corticosteroids for late preterm and elective cesarean deliveries, and antenatal corticosteroids for periviable deliveries should be considered with family discussion. However, many women with threatened preterm deliveries receive antenatal corticosteroids but do not deliver until >34 weeks or at term. The net effect is that a substantial fraction of the delivery population will be exposed to antenatal corticosteroids. There are gaps in accurate assessments of benefits of antenatal corticosteroids because the randomized controlled trials were performed prior to about 1990 in pregnancies generally >28 weeks. The care practices for the mother and infant survival were different than today. The randomized controlled trial data also do not strongly support the optimal interval from antenatal corticosteroid treatment to delivery of 1-7 days. Epidemiology-based studies using large cohorts with >85% of at-risk pregnancies treated with antenatal corticosteroids probably overestimate the benefits of antenatal corticosteroids. Although most of the prematurity-associated mortality is in low-resource environments, the efficacy and safety of antenatal corticosteroids in those environments remain to be evaluated. The short-term benefits of antenatal corticosteroids for high-risk pregnancies in high-resource environments certainly justify antenatal corticosteroids as few risks have been identified over many years. However, cardiovascular and metabolic abnormalities have been identified in large animal models and cohorts of children exposed to antenatal corticosteroids that are consistent with fetal programming for adult diseases. These late effects of antenatal corticosteroids suggest caution for the expanded use of antenatal corticosteroids beyond at-risk pregnancies at 24-34 weeks. A way forward is to develop noninvasive fetal assessments to identify pregnancies across a wider gestational age that could benefit from antenatal corticosteroids.

Cervical pessary to reduce preterm birth <34 weeks of gestation after an episode of preterm labor and a short cervix: a randomized controlled trial

BACKGROUND

To date, no intervention has proved effective in reducing the spontaneous preterm birth rate in singleton pregnancies following an episode of threatened preterm labor and short cervix remaining.

OBJECTIVE

This study was designed to ascertain whether cervical pessaries could be useful in preventing spontaneous preterm birth in women with singleton pregnancies and a short cervix after a threatened preterm labor episode.

STUDY DESIGN

This open randomized controlled trial was conducted in 357 pregnant women (between 24⁰-33⁶ weeks) who had not delivered 48 hours after a threatened preterm labor episode and had a short cervix remaining (≤25 mm at 24⁰-29⁶ weeks; ≤15 mm at 30⁰-33⁶ weeks). Patients were randomly assigned to cervical pessary (179) or routine management (178). The primary outcome was the spontaneous preterm birth rate <34 weeks. Spontaneous preterm birth <28 and 37 weeks and neonatal morbidity and mortality were also evaluated in an intention-to-treat analysis.

RESULTS

No significant differences between the pessary and routine management groups were observed in the spontaneous preterm birth rate <34 weeks (19/177 [10.7%] in the pessary group vs 24/175 [13.7%] in the control group; relative risk, 0.78; 95% confidence interval, 0.45-1.38). Spontaneous preterm birth <37 weeks occurred less frequently in the pessary group (26/175 [14.7%] vs 44/175 [25.1%]; relative risk, 0.58; 95% confidence interval, 0.38-0.90; P = .01). Preterm premature rupture of membranes rate was significantly lower in pessary carriers (4/177 [2.3%] vs 14/175 [8.0%]; relative risk, 0.28; 95% confidence interval, 0.09-0.84; P = .01). The pessary group less frequently required readmission for new threatened preterm labor episodes (8/177 [4.5%] vs 35/175 [20.0%]; relative risk, 0.23; 95% confidence interval, 0.11-0.47; P < .0001). No serious adverse maternal events occurred; neonatal morbidity and mortality were similar in both groups.

CONCLUSION

Pessary use did not significantly lower the spontaneous preterm birth rate <34 weeks in women with a short cervix remaining after a threatened preterm labor episode but did significantly reduce the spontaneous preterm birth rate <37 weeks, threatened preterm labor recurrence, and the preterm premature rupture of membranes rate.